1. Field of the Invention
The present invention relates, in general, to a probe for a nuclear magnetic resonance apparatus, and, more particularly, to a cryoprobe using a closed gas loop for a nuclear magnetic resonance apparatus, which can reduce thermal noise and improve sensitivity by rotating a rotor in which a sample is put in a cryogenic condition.
2. Description of the Related Art
Generally, when nuclear spin of an atom, which constitutes all substances, exists under an external magnetic field, the nuclear spin carries out precession around the external magnetic field. In this case, when a specific radio frequency (RF) proportional to the external magnetic field is applied from the outside, a resonance phenomenon is observed. This is called nuclear magnetic resonance (NMR).
A nuclear magnetic resonance (NMR) apparatus is used in analyzing a molecular structure and components of various substances including inorganic substances, polymers, organic substances and the like using the resonance phenomenon possessed by an atomic nucleus and is widely used in various fields, such as biology, chemistry, physics, pharmacology and the like.
As illustrated in FIG. 1, the general probe for the nuclear magnetic resonance apparatus is configured such that a rotor 1 in which a sample providing a magnetic field is placed is rotatably installed between magnets 2 providing a magnetic field, and a coil 3 providing an RF electromagnetic pulse is formed in a form of being wound around the rotor 1.
The general probe for the nuclear magnetic resonance apparatus senses a resonance phenomenon generated by the RF electromagnetic pulse of the coil 3 while rotating the rotor 1 with high pressure air, thereby detecting a magnetic resonance spectrum according to the sample. Thus, a user analyzes the sample through the magnetic resonance spectrum showing different detection peaks according to components of the sample.
However, the general probe is problematic in that detection sensitivity is deteriorated because thermal noise occurs when the rotor 1 is rotated, and thus a detection peak of the magnetic resonance spectrum becomes smoothed out.
Recently, in order to reduce the thermal noise and increase a signal to noise ratio (S/N), a nuclear magnetic resonance apparatus gas has been used, in which the rotor 1 is rotated while being cooled using nitrogen gas or helium gas.
However, in the conventional probe for the nuclear magnetic resonance apparatus, since high-priced nitrogen gas or helium gas used as a cooling gas is not recovered, but is discharged and is then dumped, it is problematic in that the operation cost is high. In addition to this, it is problematic in that the discharged cooling gas is discharged to the atmosphere, thereby having a bad effect on the environment.
Also, the conventional probe is problematic in that noise and vibration seriously occur because a mechanical compressor is used in order to supply the cooling gas to the rotor 1.
The foregoing is intended merely to aid in the understanding of the background of the present invention, and is not intended to mean that the present invention falls within the purview of the related art that is already known to those skilled in the art.